“In the first of our dialogues about the mind, Riccardo Manzotti and I established that by “consciousness” we mean the feeling that accompanies our being alive, the fact that we experience the world rather than simply interacting with it mechanically.”
“We also touched on the problem that traditional science cannot explain this fact and does not include it in its account of reality.”
“That said, there is a dominant understanding of where consciousness happens: in the brain. This “internalist,” or inside-the-head, approach shares Galileo’s view that color, smell, and sound do not exist in the outside world but only in the brain.”
“Tim Parks: Riccardo, when the internalists talk about conscious experience, they often use the word “qualia,” meaning an elementary sensation, a feeling of something, and one of their favorite examples of this is our seeing color, our experience of color. So how does it come about that we see color?”
“Riccardo Manzotti: Before answering let’s pay some attention to the language we’re using, since it may determine the way we think about the whole thing. Most people say they see a color or a colored object, a yellow banana, say. So we have subject and object; a person sees a yellow banana. Scientists and philosophers speak of our having an experience, feeling, or qualia. So now we have three things, a subject, an object (the banana maybe), and a feeling, in our heads. I fear both manners of speaking are potentially misleading.”
“the subject/object divide, not to mention the addition of a feeling or “percept,” is particularly pertinent when we talk about color.”
“science tells us there’s no color in the world. It occurs only in our brains. But, as we discussed in our first conversation, when scientists look inside the brain to see what’s going on, they find only billions of neurons exchanging electrical impulses and releasing chemical substances. They find what they call correlates of consciousness, not consciousness itself; or in this case, they find correlates of color, but not color itself. There is no yellow banana in the head, just the grey stuff.”
“The unsuspecting layman will assure you that objects simply have colors as attributes—isn’t our banana, for example, very yellow exactly the same way it’s six inches long? Well, unfortunately not, because it could easily be shown that bananas are only yellow under a certain light. Change the light and the banana might look green. But it will always be six inches long.”
“From the nineteenth century on scientists have been looking for colors inside the nervous system. First they worked on the hypothesis that colors were qualities that the retina or the optic nerve introduced into the signals that they then sent to areas further along in the brain. However, nothing satisfactory was ever found, nor is it clear what they imagined they might find.”
“the current textbook view goes like this. The world is a place where objects reflect light, sunlight being the dominant source and as it were default setting as far as the kind of light is concerned. However, each object reflects only a subset of that light. Rays from this subset enter our retina and stimulate a honeycomb of cells, known as cones, because of their conical shape, whose function is to react differently to different portions of the visible spectrum (we remember of course that only a small part of the vast electromagnetic spectrum is visible). Most humans—animals are rather different of course—possess three kinds of cones, referred to as S, M, and L cones, depending on whether they react more vigorously to short, medium or long-range light wavelengths. The “output” of these cells is first merged together in the retina then sent via the optical nerve to various cortical areas—including the famous V4. And that’s as much as we know.”
“this is a theory of color that does not need the notion of colors. I suppose the reason is that however carefully you follow neural signals from the retina along the optic nerve and across the brain you don’t actually come across anything like a color, or anything that explains color perception. You could almost say that the notion of color is useless to color science, unless…”
“Parks: Unless?”
“Manzotti: Unless we bring consciousness back in the picture. Colors are something we experience, individually and collectively. But without our experience of color, science would have no reason to suspect its existence.”
“Rather than insisting that the same pixels should always appear as the same color and talking about an appearance/reality gap what science should be doing is accepting the reality of conscious experience and questioning its own obviously imperfect understanding of what constitutes color.”
“Parks: I recall now how the neuroscientist Christof Koch claims that our experience of color is “a con job.” David Eagleman talks about vision being the result of “fancy editing tricks.” The philosopher Eric Schwitzgebel accuses us of being “ignorant and prone to error” about everything we see. A moral nuance is smuggled into the debate, as if there were something shabby and lazy in the way we see the world. It feels like we’re being blamed, or condescended to, for not perceiving things as science thinks we ought to.”
“Manzotti: Exactly. Kitaoka’s illusion—and there are many others like it—becomes a flash point where the assertions of science in the Galileo tradition clash with the validity of our conscious perception.”
“what we need to do is to get beyond the idea that consciousness is a “representation” of the world at all. Maybe it is simply reality. Maybe, as I hinted at the beginning, we have to do away with that subject/object distinction which lies behind this whole discussion.”
“This is the second in a series by Riccardo Manzotti and Tim Parks on consciousness.”